Shaker grate construction



May 29, 1945. c. v. cARRoLL SHAKER GRATE CONSTRUCTION 2 Sheets-Sheet 1 Filed Aug. 7, 1944 c.y v. Y CARROLL SHAKER GRATE CONSTRUCTION May 29,11945.

Filed Aug. '7, 1944 2 Shets-Sheet 2 n Nw mw Mnm,

K 05. JG. B9

InQenior- CHA/L Es KCA/@ROLL paul, paul to megs Patented May 29, 19.45 .l I n OFFICE Charles V. Carroll,A Minneapolis, Minn?, assignor to Win. Bros Boiler`& Manufacturing Co.,.Min neapolis, Minn.,` a corporation of lVIinnesota Application .August 7, 1944,3.Serial No. 548,399 I.

H i 6V Claims. (Cl. 11D9-39)' f' y n This invention relatesto furnace `gratos and solidly-positioned on thefurnace foundationand particularly to shakergrates for smalLinedium isseatediin refractory as illustrated .at 2l. Upon 'aridlarge size-boilers and furnaces wherein solid the vrear -cross vframe member there ispositioned ifuel is' supported upon grate surfaces that are a grate cap member 2,2 havingairslots 22a thererno'vable for shaking 'fdownor dumping the ash f 5 -in forfee'dingcombustion air .into the rear edge of `acc'ux-nullation2thereon` r'lfhe invention relates in the fuel bed. Referring to Figure 3 itv will be particular tol grate surfaces Lcomposed of a pluobservedA that the :side rails 'II and I2 of the rality ofgrate bars(yr-.sectionssupported vupon frame "are provided with-suitable caps II* and 'atrans-verse support orv carrier bar. Il' having air slots ,213,andf24 therein forfeeding It is an robject of `.the invention to provide an 1u 'airinto thermarginal edges 'of the solid fuel bed improved grate 4designof .rugged construction `supported upon the'grate. capable: of withstanding :heavy service overlong The rails Il :and 12 are `provided with bearing periods andl capable of ibeng easily serviced. It notches `25. and 26 at evenlyspaced intervals along is also'anvoloject fof .ther invention. ato provide an the side'rails. The hearing notcheshave a slightimproved. carrienbarpand grate baponstruction "11o 41y conical I bottom surface .25a and 26a, and capable'of a maximum stability, and capable of `straiglfit-.sidewalls Zib'and 2Gb for convenience providing 'a `relative motion `betweeny grate bar inmanufacture .and in order to centralize the :and carrier; so as to facilitate clearance of carrier'barll and reduce frictionoftthe carrier .clinkers and. hardlfash Aaccumulations without lfstllb` Shafts 15' and 25' in the notchesdislcdgement. ofathe grate bar. .from the .carrier Clao Y Into thefoppostely spaced notches 25 and 26 :baronwhichit is supported;y Itis a further obori-the tworails there are tted the stub end jectnofthe inventionto 'provide'improved simple, shafts '25' and 26 of `a carrier 'bar generally dessymmetricaL-yet rugged, carrier, bar and associ- 4ignated 28.@ The carrier bar. has an intermediategratebar designs capable of -eitherright-hand ate grate lbar Supporting surface` of the CrOSS Sec- -orfleft-hand mounting ,of-the carrier bar that 2o tion' 'shownat 30 in Figures 1 and 2. .f The Carrier may be manufactured easily withoutthenecesblr 23 iS Y'DIUl/ided With Cylindrical Stub Shafts sity of complicated moldings,V Y 2i'` and"26' which 4fit into the bearing notches 25 `Other objects of: the invention are those inand 26,' respectively.,1the stub shafts being loherent in the .apparatus herein illustrated, decated at the .level `shown in lFigure 3 so that the scribed and claimed.v 30 lcenterofthestub` shaftis ata level32, as illus- I The invention is illustrated with reference to tratd'v-infFE'I-IFBS land. `The Stub Shafts are the drawings in which f flattened olf .at .the top if desired. The: inter- Figure 1 is a' fragmentary side elevational view, 4mediate portion ofthe carrier bar has a cross partly in section, illustrating the invention and section similar to the cross section of a railroad showing, in full lines, the grates in normal oper- 35 -ra'.'ilexcept thatthebase flange and vertical web ating position and showing, in dotted lines, the lare somewhat 'thicker than in a railroad rail. grates in elevated ash shaking or dumping posi- The head portion. 3,3 is generally rectangular tion; l having ailatupperfsurface 34 and vertical side Figure 2. is a fragmentary View corresponding Walls'li: At the lower edge of the side walls -35 .tolthat shown in Figure 1 except that a grate bar 40 the' walls ,blend through "the curved surfaces 36 is shown in arnoved position such as it assumes -in'tothe thickened web 3l which in turn is curved under certain conditions of operation; Vinto'the Abasel:.section 38.* It will be noted that Figure 3 is an `enlarged. fragmentary cross secthe :sidewalls of the base portion, indicated at 39, ltional view taken along the .line 3--3 of Figure 1, vslanted outwardly from top to bottom. The

Throughout the drawings corresponding nu- 45 web 31 may be4 `extended somewhat-below the -merals referto corresponding parts. =bottom=flange 38, as indicated lat 4D., and at one `The furnace includes a base frame generally tpoint :along the' .length of vthe carrier bar thereis `designated I0 ,composed of side and/or center 'provided an integral downwardly extending car- Lrails IIV and'fIZ and `cross frame members I3 and `rierbar lever .142 whichv iscaatst integralwith the I4. The front'cross frame member I3 isprovided 50 ycarrierfhar and is;providedwith integral stiienwith air slots l5 and an upper grate surface I6 'ing gussets 43,'-+43'.-.

`o`f any suitable design,`and is fitted into the fur- The leversi42 are verticalwhen the grate surnaceframe construction as illustrated at I8 and lface. is-innorma1;(here'l11ustrated as level)r posiv may be cemented in place by suitable refractory tidx'i; and thexlevers are, towardone end of the I9. Therear crossframe member is likewise carrier-barst Furthermore the carrier bars are nur towards the back of the furnace or one in one direction and the other in the other direction and the shaker levers brought out one on the left side and one on the right side of the furnace. Thus a wide variety of grate andl shaker arrangements are possible by using the symmetrical carrier bar .construction here shown having the vertical shaker lever 42. The lower ends of the carrier bar levers 42 are nished in a curve, as shown at 44, and is apertured at 45, and the lower ends of all of the carrier bar levers 42 are tied together by pairs of spaced tie bars 41 having downwardly protruding portion 48. to which the shaker-link 49 is attached, located one on each side of the levers 42.

Upon the rail shaped intermediate section of the carrier bar 28 there is positioned a grate, which may be a single large grate casting reaching across from one rail to the other, or a plurality of grate bars suchas those here illustrated and generally designated 50. The grate bars 50 which are merely illustrative are here shown as identical construction and hence only4 one need be described. Each grate bar has a thickened head portion 5I of generally rectangular cross section and having a length and side elevational shape as illustrated in Figures 1 and 2. The fuel bed supporting surface of the grate bar head 5| and the sides thereof are provided with a plurality of notches for suitably supporting the solid fuel bed and for supplying combustion air there.- to. Any suitable design may be used for the grate bar head, though I preferthe design herein illustrated and more fully described in my co.

pending application Ser. No. 548,398, entitled Grate, led concurrently herewith. The grate bar head is undercut asillustrated at 52 and is chamfered as illustrated at 53 so that there is a slight overlapping of the grate bars positionedv on adjacent carrier bars when the normal grate lever is positioned as illustrated under the bracket 55 in Figure 1. The undercut portion 52 of the rearmostV tier of grate bars overlaps the cap plate 22, as illustrated in Figures 1 and 2,'of the chamiered edges 53 of the frontmosttier of grate bars are overlapped by the tip portion I1 of the end cross frame and grate member I3, as likewise illustrated in Figures 1 and 2. Thus when the grate is in level position there is an unbroken` fuel bed supporting surface, as shown in Figure 1.

Each of the grate bars is provided with a downwardly depending central web 51 of suitable thickness'adequately to support and stiften the head portion 5I of the grate bar. along the grate bar the web 51 is notched from the bottom so as to nt the general contours of the rail shaped intermediate portion of the carrier bar. Thus, as will be observed in Figures 1 and 2, the notch generally designated 58 has a` con-A tour such that it nts in abutment with the side wall39 of the base flange and extends along vthe line dened by side wall 39 to the point 59 and thence verticallyin contact with'the .side Wall ,35 of the head `portionof'thecarrierzbannl'fhe At one place 7 The clearance at 64 and the very slight clearance between the side wall 33 of the carrier bar and the corresponding surface 33' of the grate bar permits a slight relative motion of the grate barwith reference to the carrier bar, as illustrated for the grate bar 50A in Figure 2. When i the carrier bars are oscillated by means of the links 4S and 41, ashes are shaken down into the ash pit below the grate surface and then when the link '49 is moved to a position such that the grate bar should be in the level position shown in Figure l, it sometimes happens that ashes or clinkers Will lodge between the undercut tip 52 of a grate bar such as that shown at A and beveled surface 53 of the grate .bar 50, Figure 2, andthe ash or clinkers 65 so lodged will not permit the grate bar 50A to resume its normal level position. When this happens the grate bar 50A so aiected, rotates slightly with reference to its carrier bar 30A and shifts the clearance 64 to the opposite side as shown at 64', thus bringing the surface 6I. and the surface 33 into engagement with the surfaces 39V and 33 of the carrier bar, respectively. Any dislodgement of the grate bar 50A under suchconditions is .prevented by the move` ment of the lug 63 under the bottom surface of the lower liange 30 of the grate bar. The degree 'of angularity between the vertical edge surface 33 of the grate bar head portion and the adjacent boundry 33 of the grate bar is determined by the desired and permissible degree of motion between the grate bar 50Aand its carrier bar. The grate bar 50A thus out of level position does not prevent the remaining grate bars on the same or other carrier bars from resuming their normal level conditions.

Along the entire boundary of the notch 5B the ilange 51 is thickened at each side so as to form a thickened border G6 running entirely around the notch. This serves adequately to stiffen the web 51 where it is cut away at the notch 58. It will be noticed that a greater portion of the grate bar overhangs the carrier bar at one side of the notch 5S than at the other side, as illustrated by the comparative sizes of the brackets '68 and 69, Figure k1. Accordingly there is a tendency for each grate bar to assume the position shown in Figure l. The relatively close iit between the upper head portion 33-34-35 of the carrier bar and the corresponding portion of the notch and the dimension and position of the side wall of the notch 58 in contact with the surface 39, prevents the carrier from upsetting due to the overhanging weight on the end 63 or due to the fuel load on the grate bar. In addition the heavy overhanging end of each grate bar is supported due to the overlap with the short end of the grate bar on the next carrier bar as illustrated at in Figure l, and this also adds stability to the mechanism.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that I do not limit myself to the specific embodimentsherein except as defined vby the appended claims.

What I claim is:

1. A furnace grate comprising spaced grate side frame members having spaced carrier bar journal recesses therealong, carrier bars extending from,

bar supporting portion, each such grate bar being shaped to include a solid fuel supporting upper surface extending on one side of the carrier bar a greater distance than on the opposite side so as to be overweighted on said extending side of the carrier bar, said grate bars being provided with a downwardly extending supporting iiange that has an upwardly extending notch along its lower edge so as to receive the carrier bar, said notch being slightly unsymmetrical about the vertical centerline of the carrier bar at the level of the upper ange thereof and having a dimensional width and shape so as to rest under normal conditions, against the upper substantially iiat surface of the upper ange and embrace with slight clearance the edges of said upper flange, said notch also being unsymmetrical about the vertical centerline of the carrier bar at the level of f the lower flange thereof, and shaped to rest against the edge of said lower iiange corresponding to the overweighted side of the grate bar and to rest in substantiallw spaced relationship to the opposite edge of said lower ange so as to Vprovide a substantial clearance space and a lug on the wall of the notch extending toward and below said lower iiange substantially across said clearance space.

2. The apparatus of claim 1 further characterized in that the depending stifening and supporting ange of the grate bar is thickened around the margins of the notch.

3. The apparatus of claim l further characterized in that the end of that portion of each grate bar fuel supporting surface that extends the greater distance from the carrier bar on which it is supported, is undercut and the opposite end of the fuel supporting surface is chamfered to fit the undercut portion of the corresponding grate bar on the next carrier bar.

4. The apparatus of claim l further characterized in that means is provided for rotating the carrier bars a fraction of a revolution in a direction to elevate those end portions of the grate bars thereon that extend the greater distance from the carrier bars.

5. The apparatus of claim 1 further characterized in that the trunnion ends of the carrier bars protrude endwise from the I-shaped intermediate section at about the level of the upper iiange of the I-shaped section.

6. The -apparatus of claim l further characterized in that the I-shaped grate bar supporting portion oi the carrier bar has a substantially Wider lower flange than upper flange.

CHARLES V. CARROLL. 

